Polish scientists have developed the concept of a simple “chemical computer” that would be structured around moving microdroplets of water instead of electrons. Such a computer could be used to process information in extreme environments where standard computers could fail.

The concept for the innovative computer was developed in joint research pursued by scientists from two institutes run by the Polish Academy of Sciences in Warsaw—the Institute of Physical Chemistry and the Institute of Physics—aided by colleagues from the University of Jena in eastern Germany.

Computer simulations involving cancer databases have confirmed the validity of the new concept, which opens the door to a wider use of chemical methods for processing information, the scientists say.

Under appropriate conditions, so-called oscillating chemical reactions can occur inside a droplet of water. If there is more than one drop and they are in contact with one another, the resulting chemical waves can penetrate neighboring droplets and disperse throughout the complex. This phenomenon is well known to researchers who are attempting to make use of it for the chemical processing of data.

The propagation of information through a droplet system depends on its geometrical arrangement. Until recently, scientists did not know how to shape microdroplet complexes to handle specific tasks. The scientists at the Polish Academy of Sciences’ Institute of Physical Chemistry in Warsaw have suggested that instead of laboriously designing complex systems of microdroplets for a specific purpose, it is better to first produce a general-purpose system and then try to teach it specific tasks.

“We adopted a strategy that is used with great efficiency in nature,” says Prof. Jerzy Górecki from the Institute of Physical Chemistry. “Let’s look at ourselves, for example. After all, our brain didn’t evolve to recognize letters, for instance. First the brain came into existence and only then did it learn to read and write.”

He says a similar approach should be used for complex microdroplet systems that process information. “Our proposal is therefore as follows: first let’s make a system of chemically interacting microdroplets and only then see what it can do.”

The research on the chemical processing of information using microdroplet systems is financed by the Polish Ministry of Science and Higher Education, the Foundation for Polish Science and the European Union.

The researchers’ concept of the “chemical computer” is based on the so-called Belousov-Zhabotinsky oscillating reaction. Oscillation reactions are common in living organisms; in humans, they underlie the formation of the spinal vertebrae at the stage of embryonic development and are responsible for the contractions of the heart muscle, for example.

Konrad Giżyński, a Ph.D. student at the Institute of Physical Chemistry, says that in the Belousov-Zhabotinsky reaction, “the passing of a chemical front is accompanied by changes in ion concentrations leading to a change in the color of the solution.” When the reaction occurs inside a droplet, he explains, “clear pulses radiating in all directions can be seen within it under the microscope. The bigger the drop, the more often it pulsates.”

Chemical pulses in complexes of adjoining droplets spread like electrical stimulation in nerve fibers. The Institute of Physical Chemistry researchers used pulse frequencies in individual drops to encode information.

While systems that process information chemically are slow and cannot replace traditional computers, their important advantage is that they can work in extreme environments, for example under high pressure or in high temperatures where modern electronics often fail.